The present invention concerns filters, in particular air filters. More particularly, the present invention concerns the characterization of filter cartridge seal impermeability, and more precisely impermeability to air.
Air filters are commonly used in industrial devices to separate gases from the particles they contain. The air filter may be used at the exit point of a device, to purify gases prior to release into the atmosphere; or at the entry point of a device to purify the air or gas used inside the device, for example at the entry point of a gas turbine compressor.
By design, air filters are built to separate particles from gas, retaining them in a manner comparable to a sieve. The filter's interstitial spaces block the passage of particles while still enabling gas or air to flow. However, the particles retained in the filter place limits on efficient filter volume; and cleaning or replacement of the filter becomes necessary following a certain amount of usage. Filters are thus built in the form of cartridges. The cartridges are equipped with sealing means comprising attachment means and one or several gasket seals, which enable easy and fast replacement of the filter when it is obstructed or congested.
However, in view of enabling proper function of the filter, it is also necessary to ensure that the filter cartridge and its sealing means are tight or impermeable to air or gas, to make sure that the circulating air or gas is effectively crossing the filter, and not taking a parallel path along which no filtration occurs.